Conventional flow regulators and transducers provide and maintain a constant flow rate independent of changes in the pressure at measured at either the inlet or the outlet. To maintain the desired flow rate, conventional flow regulators and transducers incorporate a fixed orifice calibrated to the desired flow capacity (gallons per minute (gpm), liters per minute (l/min.) or standard cubic inches per minute (SCIM)). Because each orifice is calibrated to a specific flow rate, it is necessary to select and employ a new orifice in order to modify the flow rate for a given application.
In operation, these known flow regulators and transducers convert a voltage or current signal into a corresponding air pressure at the specified flow rate dictated by the orifice. Flow regulators and transducers controlled in this manner are effective across a limited range of pressures. Outside of this limited range, known flow regulators and transducers experience oscillation and overshoot due to the fast switching between off and on required for control.
The necessity of maintaining and storing multiple flow regulators and transducers required to cover a wide operational range increases the cost of ownership and carrying costs incurred by the user.